Cup Orientation

I have a Form 2. I would like to print a cup (5 oz) with thin walls (0.040 in). Other dimensions are: height 2.5 in, bottom diameter 1.8 in, top diameter 1.5 in. Could you give an advice about the best orientation for this cup? Thanks!

For cylindrical cup shaped designs, I often orient 30 degrees in the X or Y axis This makes cleanup of support structures on the bottom of the print relatively easy and for most geometries, you can get away with disabling internal supports.

Frew, does this mean that the central plane of the cup will be parallel to the build platform and the bottom of the cup will be perpendicular to the build platform?

I’m not sure I entirely understand. The Z plane of your cup would be oriented at a 30 degree angle to the platform.

I attached a screenshot from the FormLabs software. Is this the correct orientation?

I’m having a little bit of trouble figuring out the angle from the picture. You should be able to disable internal supports with a steep enough angle. If you upload the .form file, I can modify it for you.

I don’t have .form file but I have STL file with a coordinate system (see my attachment). I oriented a cup at a 30 degree angle to the platform. Will it help? Assy - BSD Cup (For FormLabs).STL (568.8 KB)

If you use the save function in PreForm, it will create a .form file for you. This is how we save things like orientation and support structure placement. I’ve uploaded a .form file with the orientation I’d typically use. This is somewhat less supported than we usually recommend (hence the shaded red region), but eliminates the need for internal supports and is successful for most geometries. A safer orientation would be a 45 degree angle with internal support enabled.

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Thank you very much for your help! I will try to print the cup next week.

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Looking forward to hearing how it goes!

FWIW the majority of my prints are cylindrical, cup shaped prints. I have had great success with @Frew’s recommendation although I normally go just 15%-20%.

We have pushed the printer so far as to print this at nearly full build volume with the bottom of the cup completely flat on the platform.

I just make sure to add some extra support around the bottom/outside of the item (note red supports are ones I added manually). Also I’ve learned from experience if you are going to go this route 0.75 should be min point size.

I’m thinking this orientation, however, will lessen the life of my resin tank?

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The recommendation for 30 degrees is based in part off of the design guide. The minimum recommended overhang angle is 19 degrees. Below that, some degree of bridging is likely to occur. 30 degrees is pretty conservatively within the minimum recommended overhang and results in a relatively clean bottom surface.

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I tried to upload this .form file and I got a message: “Scene corrupted.” What is wrong?

This can happen between incompatible versions of PreForm. Make sure you’re running the latest version and let me know if you’re still having trouble opening the file.

Thanks! I started my print. It will take about 5 hours.

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I printed the cup (see 8 pictures). The inside is OK but the outside has layers showing in the area between two planes parallel to the build platform (from the lowest point of the bottom to the highest point of the top). Is this the suction effect (an enclosed cavity is facing the resin tank)? Do I have to add a hole in the bottom (center)? Maybe, the angle should be different. The plane that goes from the lowest point of the bottom to the highest point of the top should be parallel to the build platform. This angle will be about 43 degrees (see 3 screenshots).


Thanks for all of the images! Based on the banding ending where you’re first tangent to the edge of the cup, I do suspect this is from suction forces and that’s something I should have considered originally. Adding a small drain hole towards the bottom of the cup should correct this issue. It’s also possible that we were a bit too precarious by disabling internal supports but I would try adding a drain hole first to see if that corrects the issue.

Thanks! I would like to try adding a drain hole. But then I’ll have to recreate the support that you created for me. I think that it’s not possible to add the drain hole in the form file that you gave me. Is this correct?

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